Because it’s very obviously illegal. You aren’t allowed to arrest members of congress for doing stuff in congress even if they do it extremely wrong. It isn’t a crime. He’ll need his caucus to stick together completely to win and this would destroy it

Overthrowing the government isn't "doing stuff" and it's already illegal.

Attempting to overthrow the government is a crime and the speech and debate clause does not automatically insulate you from it

This doesn’t even make the playbook of “extreme things of questionable legality that may nevertheless be necessary.” It’s just straight up illegal.